<div id="popUp" class='modal' style="width: 400px; height:150px; border: 1px solid black; position: absolute;"> 
    <div class="content"> 
        <h1>Erro</h1> 
        <div class="msgErro">
            Já existe um usuário com esse login. Preencha novamente os campos para adicionar um usuário com outro login.
            <input type="button" class="botao" value="Ok" onclick="{location.href='<?php echo Mapper::url('/usuario/adicionar');?>'}"/> 

        </div>
 </div> 
</div>
<style type='text/css'>
.modal 
{
    position: absolute;
    top: 25%;
    left: 35.5%;
    z-index: 5000;
    background-color: #FFF;
}
.msgErro 
{
    margin: 20px 25px 20px 25px;
    
}
.botao {
    position: relative;
    cursor: pointer;
    line-height: 22px;
    font-weight: bold;
    font-size: 11px;
    color: #333333;
    background: #F9F9F9;
    border: 1px solid #B5B5B5;
    border-radius: 3px;
    background: -webkit-gradient(linear, 0 0, 0 bottom, from(#FFFFFF), to(#F0F0F0));
    background: -webkit-linear-gradient(#FFFFFF, #F0F0F0);
    background: -moz-linear-gradient(#FFFFFF, #F0F0F0);
    background: -ms-linear-gradient(#FFFFFF, #F0F0F0);
    background: -o-linear-gradient(#FFFFFF, #F0F0F0);
    background: linear-gradient(#FFFFFF, #F0F0F0);
    -pie-background: linear-gradient(#FFFFFF, #F0F0F0);
    behavior: url(style/PIE.htc);
    float: right;
    margin-top: 20px;
    width: 100px;
}
.botao:hover {
    color: #000000;
    border: 1px solid #000000;
}
</style>